They take your money and then dissappear

I was happy to be offered a good settlement from them for my absa credit card which was paid on 14th Dec, but up till now, I have not received my paid up letter. When I call in, they keep saying it will be done at the end of the week and it's never done, and if I have to email them, they never respond and just ignore the mail but when it was time for collecting money, they would constantly call and email. Also, I think they did do a bureau update but didn't do it fully because my balance for the credit card on my credit report is still showing minus the R10 000+ I paid as a discounted settlement. Since it was a discounted settlement made within time frame, entire remaining balance was supposed to be written off after payment allocation but they only updated minus R10 000 and still reflects that I owe R14000. I want my paid up letter because this is affecting me when applying for anything because it's a large debt amount which was settled on 14th December!